A basic problem is caused by birds defecating on structures and vehicles of all types including buildings, walls, bridges, parked automobiles, as well as boats and ships. The excrement is unsightly and may cause health problems by attracting germs and insects. Also the excrement on walking surfaces may form a slippery surface causing persons to slip and fall.
Over the years many means to flush, chase, or scare birds have been used. However, birds are known to accommodate to loud noise (e.g. propane cannons), and models of their enemies (e.g. snakes, owls etc.) if they are not caused any harm or injury by the sound or devices. The following excerpts from reference 1 summarizes the situation: "The success of attempts to frighten birds away from any given area depends on our understanding of their reactions to repellent stimuli. In the interests of self-preservation, all birds react automatically to unfamiliar sights and sounds. Thus, almost any loud noise or unusual object will initially produce an effect--at least an increase in wariness or readiness to flee. However, if birds continually reacted this way to all miscellaneous noises and objects, they would be constantly alarmed. This, of course, would interfere with other necessary activities. Feeding, for example, might be disrupted to the point of starvation. To counteract this, then, birds slowly learn to ignore noises and objects as they become familiar and prove harmless . . . Recognizing that birds learn to ignore a scare device through repeated experience without any adverse effect, we must proceed in such a way that learning cannot take place. In principle, success can easily be accomplished by: (1) never using the same scare device often enough to permit learning; (2) making certain something unpleasant, such as shooting a member of the flock, occurs simultaneously with the scare device often enough to teach the birds that there is cause for real alarm . . . " However, in many situations, it is desirous to not harm or injure the birds, especially if endangered species are involved.
Currently available methods to control bird pest problems which do not involve injuring the animal are categorized as follows:
1. Visual Scare Methods involving devices e.g., scarecrows; replicas of owls, pigeon hawks, snakes and cats., flashing lights., and balloons with surrealistic eyes; all of which may exhibit movement due to the wind or even internally driven systems. PA1 2. Sonic Scare Methods involving devices audible electronic alarms; and ultrasonic repellents involving devices e.g., stainless steel PA1 3. Passive Physical Methods needle strips; nets; and metal spiral barriers. PA1 4. Chemical Methods involving liquid or gel chemical repellants. PA1 5. Electrical Shock involving exposed wires energized with high voltage, but low amperage. According to the excerpt above, the use of any one of the scare methods in the first two method categories will not train birds to permanently leave an area to be protected since the birds slowly learn to ignore the scare objects or noises as they become familiar and prove harmless. The items in the last three method categories can not be used in the area frequented by humans, such as boat decks, porch floors, railing, exterior corridors, etc.; since the needle strips, nets, wires, and metal barriers may be physically harmful to human and chemical repellants may cause toxic, slippery and/or unslightly surfaces.
Thus, there is a need for a method which sufficiently causes unpleasant experiences for birds and other wild animals without injuring them such that they do not return to the area where they experienced the effect of the method. There is also a need for a method to aid in the training of pets, e.g. dogs and cats; to avoid certain areas, such as furniture or selected rooms in a house without causing physical injury to them.